Shears



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SHEARS No. 602,360. Patented Apr. 12, 1898.

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A. PROHASKA.

SHEARS I Patented Apr. 12, 1898.

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UNITED STATES PA ENT FFICE.

SHEARS.

SPECIFICATION forming part of Letters Patent No. 602,360, dated April12, 1898.

Application filed December 31,1896. Serial No. 617,636- (No model.)

To all whom it may concern.- Be it known that I, ANTON PROHASKA, asubject of the Emperor of Austria-Hungary, and a resident ofPhiladelphia, Pennsylvania, have invented certain Improvements inShears, of which the following is a specification. i

The object of my invention is to so construct shears that the cuttingedges of theblades will be at all times in contact throughout the entirelength of the shears Without increasing the'friction to such an extentas to prevent the easy working of the same. This object I attain in thefollowing manner, reference being had to the accompanying drawings, inwhich- Figure l is aview of a pair of shears, illustrating my invention.Fig. 2 is a sectional Fig. 3 is a perspective View of the spring-plate.Fig. 4 is a perspective view of the bearing-block. Fig. 5 is a view of apair of shears, illustrating a modification of my invention; and Figs. 6and 7 are views of other modifications of the invention.

A A are the two blades of the shears, secured together by thepivot-screw a in the usual manner. The screw is adapted to the threadedopening in the blade A, and its head is adapted to a countersunk openingin the blade A. Usually this screw is tightened, so that the cuttingedges of the two blades will be in contact during the opening andclosing of the shears; but when the blades are so adjusted they are noteasily operated, and consequently the general practice has been toloosen them to such an extent that'they can be freely operated and torely on the hand to draw the cutting edges together, so that they willmake a clean cut. I overcome this objection by making a chamber'a in theblade A, and in this chamber I mount a bearingblock B, the end of whichrests upon'the surface of the blade A, directly back of the pivot, and Iregulate the pressure of this bearingblock by a spring 1), in thepresent instance in the form of a plate. This plate-spring D is securedto the bladeAbyaconfining-screw d, adapted to a threaded opening in theblade A, so that by turning this screw (1 the pressure of thebearing-block B upon the blade A can be regulated.

In order to keep the spring-plate D from moving sidewise, I preferablyperforate it at 01, so that the projectionb of the block will enter theperforation, and in order to prevent the pivot-screw a from turning inthe blade A, I form the end a ina square or other shape and extend thespring-plate B, so that the forks d of its end will extend on each sideof the pivot-screw, as shown in Fig. 1, so as to prevent the said screwfrom turning after be ing once adjusted, as it is not necessary inshears made in accordance with my invention that the pivot-screw shouldhold the blades tightly against each other. In fact,it is advisable thatthey should be a trifle loose, so that they can be operated readily, andtheir cutting edges are kept in contact by the bearing of the block B ofthe blade A against the blade A.

Instead of squaring the end of the pivotscrew it may be slotted, asshown in Fig. 7, and the end of the spring-plate made in the form of atongue adapted to the slot.

Many modifications of this invention may suggest themselves. Forinstance, in Fig. 5 I have shown the spring-plate extending only to thebearing-block. In Fig. 6 I have shown a ball B as a substitute for thecylindrical bearing-block shown in Fig. 1. In Fig. 7 I have shown a balland a block combined, the block bearing upon the ball and the ball inturn resting upon the blade A.

I claim as my invention- 1. The combination of the shear-blades, a pivottherefor, one of said blades having two perforations back of the pivot,one perforation being plain and the other screw-threaded,

a block resting in the plain perforation and and resting upon the otherblade, a springname to this specification in the presence of plate, aconfining-screw therefor, said springtwo subscribing Witnesses. platerestin upon the bearin -block and ex- 7 v tending to the pivot-screwanc'i engaging it so ANTON PROHASKA' 5 as to preventit from turning,substantially as Witnesses:

described. CHARLES W. STENZEL,

In testimony whereof I have signed my J 0s. 11. KLEIN.

